Cancer is one of the most common causes of mortality in the U.S. Agents that can prevent the proliferation of tumor cells and/or induce their death are highly desirable in the fight against cancer. The process of tumor cell proliferation is extremely complex. Understanding tumor proliferation requires precise identification of multiple cell nuclei and detailed analysis of their phases in the cell cycle. Screening for agents able to halt proliferation and/or induce death of tumor and other cancer cells rely largely on biochemical and molecular biological approaches that are laborious and, in many instances, inadequate. Improved methods for screening cellular samples for proliferation, cell cycle phase, and/or death, as well as screening methods for identifying compounds capable of halting proliferation and/or inducing death, are needed.